As MCC stated, practice at home and enter as many contest as you can, the more you show the more comfortable you will get in the ring. Once you are confident in the ring it all will come together, if you are stressed out it will show. At county you are showing against some kids who show once a year, at the other shows some of those exhibitors have been in the ring 10 to 20 time that year. Look as at showmanship as practice for animal, go in the class with the mind set that you are going to work on presenting your animal at its best, you need to be in the right attire and present your self at your best, but concentrate on the animal just like you would in your other classes. It seems to go hand in hand, the better your animal does in their class the better you do in Showmanship and the better you do in showmanship the better your the animals do in their class.
My boys did not like to do showmanship but they did it, if for nothing else but practice for their market classes. The more they showed the better they did in both classes. It comes down to becoming confident, once you are confident you can concentrate on the task at hand, showing the animal at its best.